Low-power audio classification for ubiquitous sensor networks

Author(s):  
S. Ravindran ◽  
D. Anderson ◽  
M. Slaney
Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1636
Author(s):  
Tomas Gonzalez ◽  
Joaquim Porte ◽  
Jordi Male ◽  
Joan Navarro ◽  
Josep M. Maso ◽  
...  

Despite high costs and lengthy deployments, satellite communications have traditionally been used to provide coverage in remote areas. However, given the fact that there is no radio infrastructure available in these areas, Near Vertical Incidence Skywave (NVIS) technology has positioned itself as an attractive alternative to communicate with low-power nodes in remote areas. This type of communication works in the HF frequency range complying with STANAG and MIL-STD standards, which define a physical layer for scenarios that differ from NVIS and low-power communication. The purpose of this paper was to present the definition of a new communication physical layer based on single-carrier frequency-domain equalization (SC-FDE) based on these standards but adapted to the ionospheric communication channel. This physical layer was compared to an OFDM-based layer from a previous study. The experiments performed show that this new approach achieves better results than OFDM in terms of a higher signal quality with a higher specific BER probability. Finally, this layer was also used in the theoretical design of an NVIS gateway to link sensor network devices spanning large-scale remote areas in a secure manner in the context of ubiquitous sensor networks (USN).


Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3128
Author(s):  
Thomas Ameloot ◽  
Patrick Van Torre ◽  
Hendrik Rogier

When aiming for the wider deployment of low-power sensor networks, the use of sub-GHz frequency bands shows a lot of promise in terms of robustness and minimal power consumption. Yet, when deploying such sensor networks over larger areas, the link quality can be impacted by a host of factors. Therefore, this contribution demonstrates the performance of several links in a real-world, research-oriented sensor network deployed in a (sub)urban environment. Several link characteristics are presented and analysed, exposing frequent signal deterioration and, more rarely, signal strength enhancement along certain long-distance wireless links. A connection is made between received power levels and seasonal weather changes and events. The irregular link performance presented in this paper is found to be genuinely disruptive when pushing sensor-networks to their limits in terms of range and power use. This work aims to give an indication of the severity of these effects in order to enable the design of truly reliable sensor networks.


2012 ◽  
Vol 6 (3) ◽  
pp. 137-160 ◽  
Author(s):  
Gianni Giorgetti ◽  
Richard Farley ◽  
Kiran Chikkappa ◽  
Judy Ellis ◽  
Telis Kaleas

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